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20 package org.apache.mina.filter.compression;
21
22 import java.io.IOException;
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24 import org.apache.mina.core.buffer.IoBuffer;
25
26 import com.jcraft.jzlib.JZlib;
27 import com.jcraft.jzlib.ZStream;
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35
36 class Zlib {
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38 public static final int COMPRESSION_MAX = JZlib.Z_BEST_COMPRESSION;
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41 public static final int COMPRESSION_MIN = JZlib.Z_BEST_SPEED;
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44 public static final int COMPRESSION_NONE = JZlib.Z_NO_COMPRESSION;
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47 public static final int COMPRESSION_DEFAULT = JZlib.Z_DEFAULT_COMPRESSION;
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50 public static final int MODE_DEFLATER = 1;
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52
53 public static final int MODE_INFLATER = 2;
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56 private int compressionLevel;
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59 private ZStream zStream = null;
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62 private int mode = -1;
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74 public Zlib(int compressionLevel, int mode) {
75 switch (compressionLevel) {
76 case COMPRESSION_MAX:
77 case COMPRESSION_MIN:
78 case COMPRESSION_NONE:
79 case COMPRESSION_DEFAULT:
80 this.compressionLevel = compressionLevel;
81 break;
82 default:
83 throw new IllegalArgumentException(
84 "invalid compression level specified");
85 }
86
87
88 zStream = new ZStream();
89
90 switch (mode) {
91 case MODE_DEFLATER:
92 zStream.deflateInit(this.compressionLevel);
93 break;
94 case MODE_INFLATER:
95 zStream.inflateInit();
96 break;
97 default:
98 throw new IllegalArgumentException("invalid mode specified");
99 }
100 this.mode = mode;
101 }
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113 public IoBuffer inflate(IoBuffer inBuffer) throws IOException {
114 if (mode == MODE_DEFLATER) {
115 throw new IllegalStateException("not initialized as INFLATER");
116 }
117
118 byte[] inBytes = new byte[inBuffer.remaining()];
119 inBuffer.get(inBytes).flip();
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123 byte[] outBytes = new byte[inBytes.length * 2];
124 IoBuffer outBuffer = IoBuffer.allocate(outBytes.length);
125 outBuffer.setAutoExpand(true);
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127 zStream.next_in = inBytes;
128 zStream.next_in_index = 0;
129 zStream.avail_in = inBytes.length;
130 zStream.next_out = outBytes;
131 zStream.next_out_index = 0;
132 zStream.avail_out = outBytes.length;
133 int retval = 0;
134
135 do {
136 retval = zStream.inflate(JZlib.Z_SYNC_FLUSH);
137 switch (retval) {
138 case JZlib.Z_OK:
139
140 case JZlib.Z_BUF_ERROR:
141
142 outBuffer.put(outBytes, 0, zStream.next_out_index);
143 zStream.next_out_index = 0;
144 zStream.avail_out = outBytes.length;
145 break;
146 default:
147
148 outBuffer = null;
149 if (zStream.msg == null) {
150 throw new IOException("Unknown error. Error code : "
151 + retval);
152 } else {
153 throw new IOException("Unknown error. Error code : "
154 + retval + " and message : " + zStream.msg);
155 }
156 }
157 } while (zStream.avail_in > 0);
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159 return outBuffer.flip();
160 }
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171 public IoBuffer deflate(IoBuffer inBuffer) throws IOException {
172 if (mode == MODE_INFLATER) {
173 throw new IllegalStateException("not initialized as DEFLATER");
174 }
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176 byte[] inBytes = new byte[inBuffer.remaining()];
177 inBuffer.get(inBytes).flip();
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182 int outLen = (int) Math.round(inBytes.length * 1.001) + 1 + 12;
183 byte[] outBytes = new byte[outLen];
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185 zStream.next_in = inBytes;
186 zStream.next_in_index = 0;
187 zStream.avail_in = inBytes.length;
188 zStream.next_out = outBytes;
189 zStream.next_out_index = 0;
190 zStream.avail_out = outBytes.length;
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192 int retval = zStream.deflate(JZlib.Z_SYNC_FLUSH);
193 if (retval != JZlib.Z_OK) {
194 outBytes = null;
195 inBytes = null;
196 throw new IOException("Compression failed with return value : "
197 + retval);
198 }
199
200 IoBuffer outBuf = IoBuffer
201 .wrap(outBytes, 0, zStream.next_out_index);
202
203 return outBuf;
204 }
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209 public void cleanUp() {
210 if (zStream != null) {
211 zStream.free();
212 }
213 }
214 }